Mapping of lymphatic drainage from the prostate using filtered 99mTc-sulfur nanocolloid and SPECT/CT.

We have developed a practice procedure for prostate lymphoscintigraphy using SPECT/CT and filtered Tc-99m-sulfur nanocolloid, as an alternative to the proprietary product Tc-99m-Nanocoll, which is not approved in the United States. Methods: Ten patients were enrolled for this study, and all received radiotracer prepared using a 100-nm membrane filter at a commercial radiopharmacy. Whole-body scans and SPECT/CT studies were performed within 1.5-3 h after the radiotracer had been administered directly into 6 locations of the prostate gland under transrectal ultrasound guidance. The radiation dose was estimated from the first 3 patients. Lymphatic drainage mapping was performed, and lymph nodes were identified. Results: The estimated radiation dose ranged from 3.9 to 5.2 mSv/MBq. The locations of lymph nodes draining the prostate gland were similar to those found using the proprietary product. Conclusion: When the proprietary radiolabeled nanocolloid indicated for lymphoscintigraphy is not available, prostate lymph node mapping and identification are still feasible using filtered Tc-99m-sulfur nanocolloid.